Momentary contact electric switch with axially extending contact portion



June 23, 1970 a. THIERSTEIN. JR

MOMENTARY CONTACT ELECTRIC SWITCH WITH AXIALLY EXTENDING CONTACT PORTION 2 Sheets-Sheet 1 Filed April 9, 1968 INVENTOR. EPA/E-S'T 72/525 rs/zv, J?

June 23, 1970 E. THIERSTEIN, JR 3,517,145

MOMENTARY CONTACT ELECTRIC SWITCH WITH AXIALLY EXTENDING CONTACT PORTION Filed April 9, 1968 2 Sheets-Sheet 2 42 4 I i :1: 7% EE 5 we? 1 INVENTOR. ERNEST flames-WEN, 12.

United States Patent O MOMENTARY CONTACT ELECTRIC SWITCH WITH AXIALLY EXTENDING CONTACT PORTION Ernest Thierstein, Jr., Los Angeles, Calif., assignor to International Telephone and Telegraph Corporation, New York, N. a corporation of Delaware Filed Apr. 9, 1968, Ser. No. 719,912 Int. Cl. H01h 19/24 US. Cl. 200-153 4 Claims ABSTRACT OF THE DISCLOSURE An electrical pulse switch employing a cam which is movable in one direction to effect momentary engagement between a pair of normally spaced resilient switch contacts and is movable thereafter in the opposite direction without bringing the contacts into engagement. The switch is particularly useful in certain types of burner control apparatus such as a gas range.

CROSS REFERENCE TO RELATED APPLICATION This invention is related to and may be employed in the apparatus disclosed in copending United States patent application of Richard Grayson et al., Ser. No. 627,018, filed Mar. 30, 196 7, assigned to the assignee of the present application.

BACKGROUND OF THE INVENTION This invention relates generally to an electrical switch and, more particularly, to a motion operated switch for producing a pulse-like change in a connective condition.

There are a wide variety of applications where it is desired upon a single manipulation or setting of a knob or dial to provide a momentary electrical connection which is then broken, or conversely, to momentarily break an electrical circuit and then remake it. An example of but one such application is in certain types of burner control apparatus, such as disclosed in the aforementioned Grayson et al. application, wherein it is required to have a single burner selection knob which when manipulated routes fuel to a selected burner and provides an electrical impulse to an igniter which lights the burner. Of course, upon ignition of the burner there is no longer a need for electrical power at the igniter. It is thus desirable to disconnect the igniter immediately after ignition of the burner.

SUMMARY OF THE INVENTION According to the principal aspect of the present invention, there is provided an electrical switch in which a cam is selectively movable in one direction from a rest position to initially urge normally spaced switch contacts into connective relationship and then to disengage the same. The switch contacts are resilient or spring-like members so located with respect to each other and the cam that movement of the cam therepast in said one direction brings certain portions of the switch contacts into connective relationship and then releases them permitting the inherent spring action of the contacts to effect disconnection therebetween, and such contacts avoid engagement during return of the cam to its rest position. Thus, there is provided by the present invention a manually operable switch which produces a momentary or pulselike change in a connective condition upon manipulation from a rest position to a selection position, but effects no connection between the switch contacts upon return to the rest position.

3,517,146 Patented June 23, 1970 FIG. 1 is a top plan view of the switch of the present invention as applied to a gas burner control;

FIG. 2 is a sectional, elevational view taken along the line 22 of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2;

FIGS. 4 and 5 are perspective views of the contacts employed in the switch of the present invention;

FIG. 5 is a perspective view of the cam actuator utilized in the switch of the present invention; and

FIG. 6 is a sectional view taken along line 6-6 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in detail, wherein like reference characters designate corresponding parts throughout the various views, there is illustrated in FIGS. 1 to 3 a burner selection apparatus of a gas range, generally designated 10, which embodies the switch 12 of the present invention. Only those parts of the apparatus 10 will be described herein which are necessary for an understanding of the structure and operation of the switch 12, the remaining structure of the apparatus 10 and its operation being disclosed in detail in said aforementioned Grayson et al. application.

The apparatus 10 comprises generally an enclosure 14, a rotatable actuating shaft 16 having an end extending outwardly of the enclosure, a knob 18 aflixed onto the shaft end, and a pair of switch contacts 20 and 22 positioned within the enclosure. These switch contacts are secured to the inner upper wall of the enclosure 14 by retaining means 24 and 26, respectively, the details of which will be described later. These retaining means are formed at their upper ends to provide terminal pins 28 and 30, respectively, of a female connector 32. In the specific embodiment described herein, the terminal pins are connected to a pilot igniter for energizing the same when the contacts 20 and 22 are closed.

The actuator 34 for the contacts 20 and 22 comprises a cam 34 formed on a cylinder 35 of insulation material. The cylinder is journaled for rotation on a boss 36 of the enclosure 14 and secured to the shaft 16 for common rotation therewith by a driver 38. The driver is keyed to the shaft and has a pair of ears 40 that are received within openings 42 in the cylinder 35 for achieving a driving relation with the shaft. The cam 34 is preferably in the shape of a lobe which extends upwardly from the cylinder 35, as best seen in FIG. 3, when the cam is in its normal or rest position.

As best seen in FIGS. 4a and 4b, the switch contacts 20 and 22 are formed of spring wires which are bent into generally U-shaped elements with the bases 44 and 46 of the elements bent to provide loops 48 and 49, respectively. The lower portion of each of the contact retaining means 24 and 26 is narrower than the distance between the legs 50 and 52, respectively, of the U-shaped contacts and is folded upwardly upon itself as indicated at 54 in FIGS. 2 and 6 to provide channels in which the bases 44 and 46 of the contacts are mounted. The loop portions 48 and 49 are positioned in such channels in tight frictional relationship between the upward folded portion 54 of the retaining means and the main body portion thereof so that rotation of the contacts is prevented with respect to the retaining devices. Thus, the contacts are mounted in fixed position with the enclosure 14.

The legs 52 of the contact 22 converge toward each other, extend at an angle forwardly toward the cam 34, and terminate in generally axially extending portions 56 which are disposed on opposite sides of the cam and,

hence, within its path of movement. The legs 50 of the located at the sides of the axially extending portions 56 of the contact 22 remote from the cam 34. In other words, each of the axially extending portions 56 of the contact 22 is located between the cam 34, when in its rest position, and the adjacent leg of the contact 20. Also, as best seen in FIG. 2, the legs 50 extend below the axially extending portions 56 of contact 22 so as to lie generally transversely with respect thereto; however, the legs 50 are disposed rear-wardly of the cam 34 so as to be outside of its path of movement.

When the knob 18 is manipulated to rotate the shaft 16 and hence the cam 34 in either direction of rotation from its rest position shown in FIG. 3, the cam initially engages an axially extending portion 56 of the contact 22, pushing the latter into engagement with the adjacent leg 50 of the contact 20 causing electrical contact therebetween and thus closing a circuit including the terminals 28 and 30. Further rotation of the cam in the same direction bends both legs 50 and 52 outwardly until the cam moves past leg 52 allowing both legs of the contacts to return under their inherent resiliency to their normal position and breaking electrical contact between the contacts. Thus, during this period of rotation there is only a momentary pulse-like closing of the switch 12.

If the cam is now rotated in the opposite direction back to its rest position, it will move freely past the leg 50 of contact 20 due to the axial spacing between the two parts and will again engage the axially extending portion 56 of contact 22 pushing it inwardly. This will increase the spacing between the legs of the contact, thus not effecting electrical contact therebetween. When the cam 34 is rotated fully back to its rest position, it will release the leg 52 allowing it to spring back to its original position. The lateral spacing between the legs of the two contacts 20 and 22 is greater than the overtravel of the leg 52 of contact 22 when it is allowed to spring back toward the outside wire 50 thus insuring that the contacts do not engage when the cam 34 is returned toits rest position from an operative position.

It can be seen that by the present invention, there is provided a switch which provides an electrical pulse when operating the switch in either direction from the center or rest position of the cam 34, but does not cause a pulse when the cam is returned to its rest position. As is apparent, the switch 12 of the present invention is characterized by extreme simplicity, requiring only two formed wire switch contacts 20 and 22 and the rotatable cam 34, thus permitting inexpensive manufacture, low cost of materials, and simplification of assembly procedures.

Although I have herein shown and described my in- 'vention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of my invention, which is not to be limited to the details or applications disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent structures and devices.

What is claimed is:

1. A pulse switch comprising: movable cam means and first and second normally spaced resilient switch contacts; said switch contacts being so disposed with respect to each other and said cam means that initial selective movement of said cam means in one direction brings said cam means into contact with said first switch contact moving it into contact with said second switch contact and further movement of said cam means in said one direction releasing both of said switch contacts, said cam means being sufiiciently small in size that both said first and second contacts return to their normally spaced concontact 20 are generally vertically disposed and are dition through their inherent resiliency upon the said release of both, said cam means being movable along a path in a predetermined direction, said first switch contact being disposed bet-ween said cam means and said second switch contact and including a portion extending into the path of movement of said cam means and positioned both within and without the path, said Second switch contact lying outside the path of movement of said cam means and including a portion extending generally transversely to said portion of said first switch contact in a position outside the path of movement of said cam means to be contacted momentarily by said first Switch contact portion when said first switch contact is contacted by said cam means during initial movement thereof in said one direction.

2. A pulse switch comprising: movable carn means and first and second normally spaced resilient switch contacts; said switch contacts being so disposed with respect to each other and said cam means that initial selective movement of said cam means in one direction brings said cam means into contact with said first switch contact moving it into contact with said second switch contact and further movement of said cam means in said one direction releasing both of said switch contacts, said cam means being sufiiciently small in size that both said first and second contacts return to their normally spaced condition through their inherent resiliency upon the said release of both, said cam means being rotatable about an axis, said first switch contact being generally U-shaped with legs thereof being disposed at opposite sides of said cam .means when the latter is in a rest position and including generally axially extending portions each of which is in the path of movement of said cam means when the latter is rotated in either direction from said rest position, said second switch contact being generally U-shaped with the legs thereof being disposed outside said axially extending portions of said first switch contact and each leg being so located as to be contacted by the respective axially extending portion of said first switch contact when the latter is contacted by said cam means during rotation thereof from said rest position.

3. A pulse switch as set forth in claim 2 wherein said U-shaped switch contacts are formed of spring wires.

4. A pulse switch as set forth in claim 3 including a pair of terminals each having an end portion narrower than the distance between the legs of each U-shaped wire :switch contact, said end portion being folded upon itself to provide an open channel, a portion of the base of each of said U-shaped wire switch contacts being bent to form a loop, and the base of each switch contact being positioned in a respective terminal channel with the loop thereof tightly retained between the walls of the channel to prevent rotation of the switch contact with respect to the respective terminal.

References Cited UNITED STATES PATENTS 2,727,670 12/1955 Shore 200- X 2,989,600 6/1961 Fyfe. 3,349,358 10/ 1967 Cassedy 20068 X FOREIGN PATENTS 665,793 5/ 1929 France. 1,270,313 7/1961 France.

ROBERT K. SCHAEFER, Primary Examiner R. A. VANDERHYE, Assistant Examiner U.S. Cl. X.R. 200-6, 154, 166 

